David M. Rubenstein, the billionaire Bethesda philanthropist, will donate $7.5 million to help fix the shuttered, earthquake-damaged Washington Monument, government officials plan to announce Thursday.

The gift once again confirmed Rubenstein’s status as a generous repeat benefactor for Washington’s endangered national icons.

It comes a month after he donated $4.5 million to the National Zoo’s cash-strapped giant panda program and seven months after a $13.5 million gift to the National Archives.

The 555-foot-tall monument was extensively damaged during the 5.8-magnitude earthquake that struck the area Aug. 23, and it’s been closed ever since. The quake shook the monument violently, especially near the top, severely cracking and chipping its stone blocks. The obelisk’s elevator was also damaged but has since been partially repaired. The National Park Service has said it does not know how long the monument will be closed.

Rubenstein, the son of a Baltimore postal worker, is co-founder and managing director of the Carlyle Group, a global asset-management firm that handles $148 billion in assets, according to its Web site.

He is also a member of the board of regents at the Smithsonian and chairman of Washington’s John F. Kennedy Center for the Performing Arts, where he is the single largest donor in its history, with gifts totaling $25 million. Forbes magazine estimates his worth at $2.7 billion.

In an interview, Rubenstein, 62, said he agreed to split the estimated $15 million repair bill with the federal government. Congress has already allocated the government’s share.

Officials had indicated that they were searching for a donor to match the government funding. Rubenstein said he offered to enter “a kind of public-private partnership with the U.S. government.”

“They would put up half the money for the repairs,” he said. “As a good citizen, I would put up half of it myself.”

“I am committed to philanthropy,” Rubenstein said. “I committed to giving away a large amount of my wealth. . . . I am very involved in historic kinds of things. . . . This is something that is quite historic.”

Next month, the National Archives plans to unveil the copy of the Magna Carta he bought in 2007 for $21 million in a new, state-of-the-art display case he funded for $322,000.

He also purchased a copy of the Emancipation Proclamation, now in the White House, in 2008; a copy of the Declaration of Independence, now at the State Department, in 2009; and a rare, early map of the United States, now in the Library of Congress.

Rubenstein’s donation to the zoo last month was designed to enable continued research into the complex field of panda reproduction. The zoo has two giant pandas, but breeding has been unsuccessful for the past few years.

“I give away money to lots of different things,” Rubenstein said. “I’m always working on things that I think would be good ideas. I have some more, but nothing I'm probably going to announce at this moment.”

Rubenstein said he admires George Washington and considers the monument honoring him a symbol of the United States and democratic government.

“What greater symbol is there in Washington of our country?” he said. “I just thought it would be a good thing for the country to have it back as soon as possible.

“And I also think public-private partnerships are a good thing,” he said. “And more and more things, probably the private sector will have to help with, because the government doesn’t have all the money that it used to have.”

Rubenstein said he recalled visiting the monument as a child.

“I visited when I was a little boy,” he said. “I was probably 8 or 9. I grew up in Baltimore. My parents took me to it.”

He said he toured the monument last week, riding the elevator up but taking the stairs down. “I guess they figured at my age it was easier to walk down than up,” he said.

Rubenstein said it was his understanding that repairs would take a year. A spokesman said he did not think that there would be any kind of marker at the monument mentioning the donor.

The National Park Service announced that there would be a news conference Thursday and deferred comment until then.

But officials at the Trust for the National Mall, a nonprofit group that raises funds for improvements on the Mall, were jubilant.

“I’m so excited,” said Caroline Cunningham, the group’s president. “This is an extraordinarily generous contribution . . . and a true patriotic commitment to one of the most important symbols of our country.”

Cunningham said that Rubenstein approached National Park Service Director Jonathan B. Jarvis and said: “You got a cracked monument. How can I help?”

Rubenstein is “one of those people who’s made a commitment to pass on his wealth and invest in this country,” Cunningham said, “and I know that he feels passionately about the history of this country and preserving it.”